Researchers have found a promising way to show the edges of brain tumors in MRI scans more clearly.
The study, which offers scientists the most complete picture of brain tumors yet, is the work of a team from the University of Oxford in the UK, and was presented on Monday at the National Cancer Research Institute (NCRI) Cancer Conference 2015, in Liverpool, UK.
The edges of a tumor contain the most invasive cancercells. For surgery or radiation therapy to succeed, doctors need good maps that show not only where the tumor sits in the brain, but also where its edges are – a clear delineation between cancerous and healthy tissue.
This is important not only in order to remove all the cancerous tissue, but also because the most invasive cells are at the edge of a tumor, as one of the researchers, Cancer Research UK scientist Nicola Sibson, a professor in the Institute for Radiation Oncology at Oxford, explains:
“If we can’t map the edge of the tumor, surgery and radiotherapy often fail to remove aggressive tumor cells – and the brain tumor can grow back.
Currently, on magnetic resonance imaging (MRI) scans, you can see where the brain tumor is, but its edges are blurred. This is because the MRI spots leaky blood vessels inside the tumor. But on the edges of the tumor, the blood vessels are intact, so they do not show as clearly on the scans.
Highlights edges of both primary and secondary brain tumors
Now, for the first time, Prof. Sibson and her team have discovered a useful protein inside the blood vessels at the invasive edge of brain tumors.
In tests on rats, they showed it is possible to use the protein to define the edges of both primary and secondary tumors on MRI scans.
The protein – called VCAM-1 – is released as part of an inflammatory response caused by the brain tumor. The researchers developed a special dye that recognizes and sticks to the protein. The dye highlights the protein – and thus the edges of the tumor – on MRI scans.
An added advantage, note the researchers, is that the protein is on the inside of the vessels, so the dye can access it from the bloodstream.
Prof. Sibson concludes:
“This research shows that we can improve imaging of brain tumors, which could help both surgeons and radiotherapists with more effective treatment.”
Every year, around 256,000 people worldwide are diagnosed with cancer in the brain or another part of the central nervous system. In the UK, where the study was conducted, this figure is around 9,700, or 27 people a day.
“Brain cancers continue to have very poor survival rates,” says Harpal Kumar, chief executive of Cancer Research UK, which co-funded the study with the Medical Research Council. Kumar adds:
“The holy grail would be to be able to completely remove brain tumors with the help of this new imaging technique – reducing recurrence of the disease and saving more lives.”